package javaforce;

import java.util.Random;

/**
 * A Unix encryption which is uni-directional. Was typically used to hash
 * passwords on older Unix systems.
 */
public class UnixCrypt {

  // Provides the Unix crypt() encryption algorithm.
  // The list with characters allowed in a Unix encrypted password.
  // It is used to randomly chose two characters for use in the encryption.
  private static char m_encryptionSaltCharacters[] = ("abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789./".toCharArray());
  // A lookup-table, presumably filled with some sort of encryption key.
  // It is used to calculate the index to the m_SPTranslationTable lookup-table.
  private static int m_saltTranslation[] = {
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01,
    0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09,
    0x0A, 0x0B, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0A,
    0x0B, 0x0C, 0x0D, 0x0E, 0x0F, 0x10, 0x11, 0x12,
    0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19, 0x1A,
    0x1B, 0x1C, 0x1D, 0x1E, 0x1F, 0x20, 0x21, 0x22,
    0x23, 0x24, 0x25, 0x20, 0x21, 0x22, 0x23, 0x24,
    0x25, 0x26, 0x27, 0x28, 0x29, 0x2A, 0x2B, 0x2C,
    0x2D, 0x2E, 0x2F, 0x30, 0x31, 0x32, 0x33, 0x34,
    0x35, 0x36, 0x37, 0x38, 0x39, 0x3A, 0x3B, 0x3C,
    0x3D, 0x3E, 0x3F, 0x00, 0x00, 0x00, 0x00, 0x00
  };
  // A lookup-table.
  // It is used to calculate the index to the m_skb lookup-table.
  private static boolean m_shifts[] = {
    false, false, true, true, true, true, true, true,
    false, true, true, true, true, true, true, false
  };
  // A lookup-table.
  // It is used the dynamically create the schedule lookup-table.
  private static int m_skb[][] = {
    {
      /* for C bits (numbered as per FIPS 46) 1 2 3 4 5 6 */
      0x00000000, 0x00000010, 0x20000000, 0x20000010,
      0x00010000, 0x00010010, 0x20010000, 0x20010010,
      0x00000800, 0x00000810, 0x20000800, 0x20000810,
      0x00010800, 0x00010810, 0x20010800, 0x20010810,
      0x00000020, 0x00000030, 0x20000020, 0x20000030,
      0x00010020, 0x00010030, 0x20010020, 0x20010030,
      0x00000820, 0x00000830, 0x20000820, 0x20000830,
      0x00010820, 0x00010830, 0x20010820, 0x20010830,
      0x00080000, 0x00080010, 0x20080000, 0x20080010,
      0x00090000, 0x00090010, 0x20090000, 0x20090010,
      0x00080800, 0x00080810, 0x20080800, 0x20080810,
      0x00090800, 0x00090810, 0x20090800, 0x20090810,
      0x00080020, 0x00080030, 0x20080020, 0x20080030,
      0x00090020, 0x00090030, 0x20090020, 0x20090030,
      0x00080820, 0x00080830, 0x20080820, 0x20080830,
      0x00090820, 0x00090830, 0x20090820, 0x20090830
    },
    {
      /* for C bits (numbered as per FIPS 46) 7 8 10 11 12 13 */
      0x00000000, 0x02000000, 0x00002000, 0x02002000,
      0x00200000, 0x02200000, 0x00202000, 0x02202000,
      0x00000004, 0x02000004, 0x00002004, 0x02002004,
      0x00200004, 0x02200004, 0x00202004, 0x02202004,
      0x00000400, 0x02000400, 0x00002400, 0x02002400,
      0x00200400, 0x02200400, 0x00202400, 0x02202400,
      0x00000404, 0x02000404, 0x00002404, 0x02002404,
      0x00200404, 0x02200404, 0x00202404, 0x02202404,
      0x10000000, 0x12000000, 0x10002000, 0x12002000,
      0x10200000, 0x12200000, 0x10202000, 0x12202000,
      0x10000004, 0x12000004, 0x10002004, 0x12002004,
      0x10200004, 0x12200004, 0x10202004, 0x12202004,
      0x10000400, 0x12000400, 0x10002400, 0x12002400,
      0x10200400, 0x12200400, 0x10202400, 0x12202400,
      0x10000404, 0x12000404, 0x10002404, 0x12002404,
      0x10200404, 0x12200404, 0x10202404, 0x12202404
    },
    {
      /* for C bits (numbered as per FIPS 46) 14 15 16 17 19 20 */
      0x00000000, 0x00000001, 0x00040000, 0x00040001,
      0x01000000, 0x01000001, 0x01040000, 0x01040001,
      0x00000002, 0x00000003, 0x00040002, 0x00040003,
      0x01000002, 0x01000003, 0x01040002, 0x01040003,
      0x00000200, 0x00000201, 0x00040200, 0x00040201,
      0x01000200, 0x01000201, 0x01040200, 0x01040201,
      0x00000202, 0x00000203, 0x00040202, 0x00040203,
      0x01000202, 0x01000203, 0x01040202, 0x01040203,
      0x08000000, 0x08000001, 0x08040000, 0x08040001,
      0x09000000, 0x09000001, 0x09040000, 0x09040001,
      0x08000002, 0x08000003, 0x08040002, 0x08040003,
      0x09000002, 0x09000003, 0x09040002, 0x09040003,
      0x08000200, 0x08000201, 0x08040200, 0x08040201,
      0x09000200, 0x09000201, 0x09040200, 0x09040201,
      0x08000202, 0x08000203, 0x08040202, 0x08040203,
      0x09000202, 0x09000203, 0x09040202, 0x09040203
    },
    {
      /* for C bits (numbered as per FIPS 46) 21 23 24 26 27 28 */
      0x00000000, 0x00100000, 0x00000100, 0x00100100,
      0x00000008, 0x00100008, 0x00000108, 0x00100108,
      0x00001000, 0x00101000, 0x00001100, 0x00101100,
      0x00001008, 0x00101008, 0x00001108, 0x00101108,
      0x04000000, 0x04100000, 0x04000100, 0x04100100,
      0x04000008, 0x04100008, 0x04000108, 0x04100108,
      0x04001000, 0x04101000, 0x04001100, 0x04101100,
      0x04001008, 0x04101008, 0x04001108, 0x04101108,
      0x00020000, 0x00120000, 0x00020100, 0x00120100,
      0x00020008, 0x00120008, 0x00020108, 0x00120108,
      0x00021000, 0x00121000, 0x00021100, 0x00121100,
      0x00021008, 0x00121008, 0x00021108, 0x00121108,
      0x04020000, 0x04120000, 0x04020100, 0x04120100,
      0x04020008, 0x04120008, 0x04020108, 0x04120108,
      0x04021000, 0x04121000, 0x04021100, 0x04121100,
      0x04021008, 0x04121008, 0x04021108, 0x04121108
    },
    {
      /* for D bits (numbered as per FIPS 46) 1 2 3 4 5 6 */
      0x00000000, 0x10000000, 0x00010000, 0x10010000,
      0x00000004, 0x10000004, 0x00010004, 0x10010004,
      0x20000000, 0x30000000, 0x20010000, 0x30010000,
      0x20000004, 0x30000004, 0x20010004, 0x30010004,
      0x00100000, 0x10100000, 0x00110000, 0x10110000,
      0x00100004, 0x10100004, 0x00110004, 0x10110004,
      0x20100000, 0x30100000, 0x20110000, 0x30110000,
      0x20100004, 0x30100004, 0x20110004, 0x30110004,
      0x00001000, 0x10001000, 0x00011000, 0x10011000,
      0x00001004, 0x10001004, 0x00011004, 0x10011004,
      0x20001000, 0x30001000, 0x20011000, 0x30011000,
      0x20001004, 0x30001004, 0x20011004, 0x30011004,
      0x00101000, 0x10101000, 0x00111000, 0x10111000,
      0x00101004, 0x10101004, 0x00111004, 0x10111004,
      0x20101000, 0x30101000, 0x20111000, 0x30111000,
      0x20101004, 0x30101004, 0x20111004, 0x30111004
    },
    {
      /* for D bits (numbered as per FIPS 46) 8 9 11 12 13 14 */
      0x00000000, 0x08000000, 0x00000008, 0x08000008,
      0x00000400, 0x08000400, 0x00000408, 0x08000408,
      0x00020000, 0x08020000, 0x00020008, 0x08020008,
      0x00020400, 0x08020400, 0x00020408, 0x08020408,
      0x00000001, 0x08000001, 0x00000009, 0x08000009,
      0x00000401, 0x08000401, 0x00000409, 0x08000409,
      0x00020001, 0x08020001, 0x00020009, 0x08020009,
      0x00020401, 0x08020401, 0x00020409, 0x08020409,
      0x02000000, 0x0A000000, 0x02000008, 0x0A000008,
      0x02000400, 0x0A000400, 0x02000408, 0x0A000408,
      0x02020000, 0x0A020000, 0x02020008, 0x0A020008,
      0x02020400, 0x0A020400, 0x02020408, 0x0A020408,
      0x02000001, 0x0A000001, 0x02000009, 0x0A000009,
      0x02000401, 0x0A000401, 0x02000409, 0x0A000409,
      0x02020001, 0x0A020001, 0x02020009, 0x0A020009,
      0x02020401, 0x0A020401, 0x02020409, 0x0A020409
    },
    {
      /* for D bits (numbered as per FIPS 46) 16 17 18 19 20 21 */
      0x00000000, 0x00000100, 0x00080000, 0x00080100,
      0x01000000, 0x01000100, 0x01080000, 0x01080100,
      0x00000010, 0x00000110, 0x00080010, 0x00080110,
      0x01000010, 0x01000110, 0x01080010, 0x01080110,
      0x00200000, 0x00200100, 0x00280000, 0x00280100,
      0x01200000, 0x01200100, 0x01280000, 0x01280100,
      0x00200010, 0x00200110, 0x00280010, 0x00280110,
      0x01200010, 0x01200110, 0x01280010, 0x01280110,
      0x00000200, 0x00000300, 0x00080200, 0x00080300,
      0x01000200, 0x01000300, 0x01080200, 0x01080300,
      0x00000210, 0x00000310, 0x00080210, 0x00080310,
      0x01000210, 0x01000310, 0x01080210, 0x01080310,
      0x00200200, 0x00200300, 0x00280200, 0x00280300,
      0x01200200, 0x01200300, 0x01280200, 0x01280300,
      0x00200210, 0x00200310, 0x00280210, 0x00280310,
      0x01200210, 0x01200310, 0x01280210, 0x01280310
    },
    {
      /* for D bits (numbered as per FIPS 46) 22 23 24 25 27 28 */
      0x00000000, 0x04000000, 0x00040000, 0x04040000,
      0x00000002, 0x04000002, 0x00040002, 0x04040002,
      0x00002000, 0x04002000, 0x00042000, 0x04042000,
      0x00002002, 0x04002002, 0x00042002, 0x04042002,
      0x00000020, 0x04000020, 0x00040020, 0x04040020,
      0x00000022, 0x04000022, 0x00040022, 0x04040022,
      0x00002020, 0x04002020, 0x00042020, 0x04042020,
      0x00002022, 0x04002022, 0x00042022, 0x04042022,
      0x00000800, 0x04000800, 0x00040800, 0x04040800,
      0x00000802, 0x04000802, 0x00040802, 0x04040802,
      0x00002800, 0x04002800, 0x00042800, 0x04042800,
      0x00002802, 0x04002802, 0x00042802, 0x04042802,
      0x00000820, 0x04000820, 0x00040820, 0x04040820,
      0x00000822, 0x04000822, 0x00040822, 0x04040822,
      0x00002820, 0x04002820, 0x00042820, 0x04042820,
      0x00002822, 0x04002822, 0x00042822, 0x04042822
    }
  };
  // A lookup-table.
  // It is used to calculate two ints that are used to encrypt the password.
  private static int m_SPTranslationTable[][] = {
    {
      /* nibble 0 */
      0x00820200, 0x00020000, 0x80800000, 0x80820200,
      0x00800000, 0x80020200, 0x80020000, 0x80800000,
      0x80020200, 0x00820200, 0x00820000, 0x80000200,
      0x80800200, 0x00800000, 0x00000000, 0x80020000,
      0x00020000, 0x80000000, 0x00800200, 0x00020200,
      0x80820200, 0x00820000, 0x80000200, 0x00800200,
      0x80000000, 0x00000200, 0x00020200, 0x80820000,
      0x00000200, 0x80800200, 0x80820000, 0x00000000,
      0x00000000, 0x80820200, 0x00800200, 0x80020000,
      0x00820200, 0x00020000, 0x80000200, 0x00800200,
      0x80820000, 0x00000200, 0x00020200, 0x80800000,
      0x80020200, 0x80000000, 0x80800000, 0x00820000,
      0x80820200, 0x00020200, 0x00820000, 0x80800200,
      0x00800000, 0x80000200, 0x80020000, 0x00000000,
      0x00020000, 0x00800000, 0x80800200, 0x00820200,
      0x80000000, 0x80820000, 0x00000200, 0x80020200
    },
    {
      /* nibble 1 */
      0x10042004, 0x00000000, 0x00042000, 0x10040000,
      0x10000004, 0x00002004, 0x10002000, 0x00042000,
      0x00002000, 0x10040004, 0x00000004, 0x10002000,
      0x00040004, 0x10042000, 0x10040000, 0x00000004,
      0x00040000, 0x10002004, 0x10040004, 0x00002000,
      0x00042004, 0x10000000, 0x00000000, 0x00040004,
      0x10002004, 0x00042004, 0x10042000, 0x10000004,
      0x10000000, 0x00040000, 0x00002004, 0x10042004,
      0x00040004, 0x10042000, 0x10002000, 0x00042004,
      0x10042004, 0x00040004, 0x10000004, 0x00000000,
      0x10000000, 0x00002004, 0x00040000, 0x10040004,
      0x00002000, 0x10000000, 0x00042004, 0x10002004,
      0x10042000, 0x00002000, 0x00000000, 0x10000004,
      0x00000004, 0x10042004, 0x00042000, 0x10040000,
      0x10040004, 0x00040000, 0x00002004, 0x10002000,
      0x10002004, 0x00000004, 0x10040000, 0x00042000
    },
    {
      /* nibble 2 */
      0x41000000, 0x01010040, 0x00000040, 0x41000040,
      0x40010000, 0x01000000, 0x41000040, 0x00010040,
      0x01000040, 0x00010000, 0x01010000, 0x40000000,
      0x41010040, 0x40000040, 0x40000000, 0x41010000,
      0x00000000, 0x40010000, 0x01010040, 0x00000040,
      0x40000040, 0x41010040, 0x00010000, 0x41000000,
      0x41010000, 0x01000040, 0x40010040, 0x01010000,
      0x00010040, 0x00000000, 0x01000000, 0x40010040,
      0x01010040, 0x00000040, 0x40000000, 0x00010000,
      0x40000040, 0x40010000, 0x01010000, 0x41000040,
      0x00000000, 0x01010040, 0x00010040, 0x41010000,
      0x40010000, 0x01000000, 0x41010040, 0x40000000,
      0x40010040, 0x41000000, 0x01000000, 0x41010040,
      0x00010000, 0x01000040, 0x41000040, 0x00010040,
      0x01000040, 0x00000000, 0x41010000, 0x40000040,
      0x41000000, 0x40010040, 0x00000040, 0x01010000
    },
    {
      /* nibble 3 */
      0x00100402, 0x04000400, 0x00000002, 0x04100402,
      0x00000000, 0x04100000, 0x04000402, 0x00100002,
      0x04100400, 0x04000002, 0x04000000, 0x00000402,
      0x04000002, 0x00100402, 0x00100000, 0x04000000,
      0x04100002, 0x00100400, 0x00000400, 0x00000002,
      0x00100400, 0x04000402, 0x04100000, 0x00000400,
      0x00000402, 0x00000000, 0x00100002, 0x04100400,
      0x04000400, 0x04100002, 0x04100402, 0x00100000,
      0x04100002, 0x00000402, 0x00100000, 0x04000002,
      0x00100400, 0x04000400, 0x00000002, 0x04100000,
      0x04000402, 0x00000000, 0x00000400, 0x00100002,
      0x00000000, 0x04100002, 0x04100400, 0x00000400,
      0x04000000, 0x04100402, 0x00100402, 0x00100000,
      0x04100402, 0x00000002, 0x04000400, 0x00100402,
      0x00100002, 0x00100400, 0x04100000, 0x04000402,
      0x00000402, 0x04000000, 0x04000002, 0x04100400
    },
    {
      /* nibble 4 */
      0x02000000, 0x00004000, 0x00000100, 0x02004108,
      0x02004008, 0x02000100, 0x00004108, 0x02004000,
      0x00004000, 0x00000008, 0x02000008, 0x00004100,
      0x02000108, 0x02004008, 0x02004100, 0x00000000,
      0x00004100, 0x02000000, 0x00004008, 0x00000108,
      0x02000100, 0x00004108, 0x00000000, 0x02000008,
      0x00000008, 0x02000108, 0x02004108, 0x00004008,
      0x02004000, 0x00000100, 0x00000108, 0x02004100,
      0x02004100, 0x02000108, 0x00004008, 0x02004000,
      0x00004000, 0x00000008, 0x02000008, 0x02000100,
      0x02000000, 0x00004100, 0x02004108, 0x00000000,
      0x00004108, 0x02000000, 0x00000100, 0x00004008,
      0x02000108, 0x00000100, 0x00000000, 0x02004108,
      0x02004008, 0x02004100, 0x00000108, 0x00004000,
      0x00004100, 0x02004008, 0x02000100, 0x00000108,
      0x00000008, 0x00004108, 0x02004000, 0x02000008
    },
    {
      /* nibble 5 */
      0x20000010, 0x00080010, 0x00000000, 0x20080800,
      0x00080010, 0x00000800, 0x20000810, 0x00080000,
      0x00000810, 0x20080810, 0x00080800, 0x20000000,
      0x20000800, 0x20000010, 0x20080000, 0x00080810,
      0x00080000, 0x20000810, 0x20080010, 0x00000000,
      0x00000800, 0x00000010, 0x20080800, 0x20080010,
      0x20080810, 0x20080000, 0x20000000, 0x00000810,
      0x00000010, 0x00080800, 0x00080810, 0x20000800,
      0x00000810, 0x20000000, 0x20000800, 0x00080810,
      0x20080800, 0x00080010, 0x00000000, 0x20000800,
      0x20000000, 0x00000800, 0x20080010, 0x00080000,
      0x00080010, 0x20080810, 0x00080800, 0x00000010,
      0x20080810, 0x00080800, 0x00080000, 0x20000810,
      0x20000010, 0x20080000, 0x00080810, 0x00000000,
      0x00000800, 0x20000010, 0x20000810, 0x20080800,
      0x20080000, 0x00000810, 0x00000010, 0x20080010
    },
    {
      /* nibble 6 */
      0x00001000, 0x00000080, 0x00400080, 0x00400001,
      0x00401081, 0x00001001, 0x00001080, 0x00000000,
      0x00400000, 0x00400081, 0x00000081, 0x00401000,
      0x00000001, 0x00401080, 0x00401000, 0x00000081,
      0x00400081, 0x00001000, 0x00001001, 0x00401081,
      0x00000000, 0x00400080, 0x00400001, 0x00001080,
      0x00401001, 0x00001081, 0x00401080, 0x00000001,
      0x00001081, 0x00401001, 0x00000080, 0x00400000,
      0x00001081, 0x00401000, 0x00401001, 0x00000081,
      0x00001000, 0x00000080, 0x00400000, 0x00401001,
      0x00400081, 0x00001081, 0x00001080, 0x00000000,
      0x00000080, 0x00400001, 0x00000001, 0x00400080,
      0x00000000, 0x00400081, 0x00400080, 0x00001080,
      0x00000081, 0x00001000, 0x00401081, 0x00400000,
      0x00401080, 0x00000001, 0x00001001, 0x00401081,
      0x00400001, 0x00401080, 0x00401000, 0x00001001
    },
    {
      /* nibble 7 */
      0x08200020, 0x08208000, 0x00008020, 0x00000000,
      0x08008000, 0x00200020, 0x08200000, 0x08208020,
      0x00000020, 0x08000000, 0x00208000, 0x00008020,
      0x00208020, 0x08008020, 0x08000020, 0x08200000,
      0x00008000, 0x00208020, 0x00200020, 0x08008000,
      0x08208020, 0x08000020, 0x00000000, 0x00208000,
      0x08000000, 0x00200000, 0x08008020, 0x08200020,
      0x00200000, 0x00008000, 0x08208000, 0x00000020,
      0x00200000, 0x00008000, 0x08000020, 0x08208020,
      0x00008020, 0x08000000, 0x00000000, 0x00208000,
      0x08200020, 0x08008020, 0x08008000, 0x00200020,
      0x08208000, 0x00000020, 0x00200020, 0x08008000,
      0x08208020, 0x00200000, 0x08200000, 0x08000020,
      0x00208000, 0x00008020, 0x08008020, 0x08200000,
      0x00000020, 0x08208000, 0x00208020, 0x00000000,
      0x08000000, 0x08200020, 0x00008000, 0x00208020
    }
  };
  // A lookup-table filled with printable characters.
  // It is used to make sure the encrypted password contains only printable characters. It is filled with
  // ASCII characters 46 - 122 (from the dot (.) untill (including) the lowercase 'z').
  private static int m_characterConversionTable[] = {
    0x2E, 0x2F, 0x30, 0x31, 0x32, 0x33, 0x34, 0x35,
    0x36, 0x37, 0x38, 0x39, 0x41, 0x42, 0x43, 0x44,
    0x45, 0x46, 0x47, 0x48, 0x49, 0x4A, 0x4B, 0x4C,
    0x4D, 0x4E, 0x4F, 0x50, 0x51, 0x52, 0x53, 0x54,
    0x55, 0x56, 0x57, 0x58, 0x59, 0x5A, 0x61, 0x62,
    0x63, 0x64, 0x65, 0x66, 0x67, 0x68, 0x69, 0x6A,
    0x6B, 0x6C, 0x6D, 0x6E, 0x6F, 0x70, 0x71, 0x72,
    0x73, 0x74, 0x75, 0x76, 0x77, 0x78, 0x79, 0x7A
  };
  // Marks the size of the dynamically created schedule lookup-table.
  private static int m_desIterations = 16;

  // Converts four seperate bytes into one int.
  // <param name="inputBytes">The bytes to use for the conversion.</param>
  // <param name="offset">The offset at which to start in the inputBytes buffer.</param>
  private static int FourbytesToInt(byte[] inputBytes, int offset) {
    int resultValue = 0;

    resultValue = (inputBytes[offset++] & 0xFF);
    resultValue |= (inputBytes[offset++] & 0xFF) << 8;
    resultValue |= (inputBytes[offset++] & 0xFF) << 16;
    resultValue |= (inputBytes[offset++] & 0xFF) << 24;

    return resultValue;
  }

  // Converts an int into 4 seperate bytes.
  // <param name="inputInt">The int to convert.</param>
  // <param name="outputBytes">The byte buffer into which to store the result.</param>
  // <param name="offset">The offset to start storing at in the outputBytes buffer.</param>
  private static void IntToFourbytes(int inputInt, byte[] outputbytes, int offset) {
    outputbytes[offset++] = (byte) (inputInt & 0xFF);
    outputbytes[offset++] = (byte) ((inputInt >>> 8) & 0xFF);
    outputbytes[offset++] = (byte) ((inputInt >>> 16) & 0xFF);
    outputbytes[offset++] = (byte) ((inputInt >>> 24) & 0xFF);
  }

  // Performs some operation on 4 ints. It's labeled PERM_OP in the original source.
  // <param name="firstInt">The first int to use.</param>
  // <param name="secondInt">The second int to use.</param>
  // <param name="thirdInt">The third int to use.</param>
  // <param name="fourthInt">The fourth int to use.</param>
  // <param name="operationResults">An array of 2 ints that are the result of this operation.</param>
  private static void PermOperation(int firstInt, int secondInt, int thirdInt, int fourthInt, int[] operationResults) {
    int tempInt = ((firstInt >>> thirdInt) ^ secondInt) & fourthInt;
    firstInt ^= tempInt << thirdInt;
    secondInt ^= tempInt;

    operationResults[0] = firstInt;
    operationResults[1] = secondInt;
  }

  // Performs some operation on 3 ints. It's labeled HPERM_OP in the original source.
  // <param name="firstInt">The first int to use.</param>
  // <param name="secondInt">The second int to use.</param>
  // <param name="thirdInt">The third int to use.</param>
  // <returns>An int that is the result of this operation.</returns>
  private static int HPermOperation(int firstInt, int secondInt, int thirdInt) {
    // The variable secondInt is always used to calculate the number at the right side of a
    // bitshift. It is not used anywhere else, so I made the method parameter an int, to avoid
    // unnecessary casting.
    int tempInt = ((firstInt << (16 - secondInt)) ^ firstInt) & thirdInt;
    int returnInt = firstInt ^ tempInt ^ (tempInt >>> (16 - secondInt));

    return returnInt;
  }

  // This method does some very complex bit manipulations.
  // <param name="encryptionKey">The input data to use for the bit manipulations.</param>
  // <returns>m_desIterations * 2 number of ints that are the result of the manipulations.</returns>
  private static int[] SetDESKey(byte[] encryptionKey) {
    int[] schedule = new int[m_desIterations * 2];

    int firstInt = FourbytesToInt(encryptionKey, 0);
    int secondInt = FourbytesToInt(encryptionKey, 4);

    int operationResults[] = new int[2];
    PermOperation(secondInt, firstInt, 4, 0x0F0F0F0F, operationResults);
    secondInt = operationResults[0];
    firstInt = operationResults[1];

    firstInt = HPermOperation(firstInt, -2, 0xCCCC0000);
    secondInt = HPermOperation(secondInt, -2, 0xCCCC0000);

    PermOperation(secondInt, firstInt, 1, 0x55555555, operationResults);
    secondInt = operationResults[0];
    firstInt = operationResults[1];

    PermOperation(firstInt, secondInt, 8, 0x00FF00FF, operationResults);
    firstInt = operationResults[0];
    secondInt = operationResults[1];

    PermOperation(secondInt, firstInt, 1, 0x55555555, operationResults);
    secondInt = operationResults[0];
    firstInt = operationResults[1];

    secondInt = (((secondInt & 0xFF) << 16) | (secondInt & 0xFF00)
            | ((secondInt & 0xFF0000) >>> 16) | ((firstInt & 0xF0000000) >>> 4));

    firstInt &= 0x0FFFFFFF;

    boolean needToShift;
    int firstSkbValue, secondSkbValue;
    int scheduleIndex = 0;

    for (int index = 0; index < m_desIterations; index++) {
      needToShift = m_shifts[index];
      if (needToShift) {
        firstInt = (firstInt >>> 2) | (firstInt << 26);
        secondInt = (secondInt >>> 2) | (secondInt << 26);
      } else {
        firstInt = (firstInt >>> 1) | (firstInt << 27);
        secondInt = (secondInt >>> 1) | (secondInt << 27);
      }

      firstInt &= 0x0FFFFFFF;
      secondInt &= 0xFFFFFFF;

      firstSkbValue = m_skb[0][firstInt & 0x3F]
              | m_skb[1][((firstInt >>> 6) & 0x03) | ((firstInt >>> 7) & 0x3C)]
              | m_skb[2][((firstInt >>> 13) & 0x0F) | ((firstInt >>> 14) & 0x30)]
              | m_skb[3][((firstInt >>> 20) & 0x01) | ((firstInt >>> 21) & 0x06) | ((firstInt >>> 22) & 0x38)];

      secondSkbValue = m_skb[4][secondInt & 0x3F]
              | m_skb[5][((secondInt >>> 7) & 0x03) | ((secondInt >>> 8) & 0x3C)]
              | m_skb[6][(secondInt >>> 15) & 0x3F]
              | m_skb[7][((secondInt >>> 21) & 0x0F) | ((secondInt >>> 22) & 0x30)];

      schedule[scheduleIndex++] = ((secondSkbValue << 16) | (firstSkbValue & 0xFFFF)) & 0xFFFFFFFF;
      firstSkbValue = ((firstSkbValue >>> 16) | (secondSkbValue & 0xFFFF0000));

      firstSkbValue = (firstSkbValue << 4) | (firstSkbValue >>> 28);
      schedule[scheduleIndex++] = firstSkbValue & 0xFFFFFFFF;
    }

    return schedule;
  }

  // This method does some bit manipulations.
  // <param name="left">An input that is manipulated and then used for output.</param>
  // <param name="right">This is used for the bit manipulation.</param>
  // <param name="scheduleIndex">The index of an int to use from the schedule array.</param>
  // <param name="firstSaltTranslator">The translated salt for the first salt character.</param>
  // <param name="secondSaltTranslator">The translated salt for the second salt character.</param>
  // <param name="schedule">The schedule arrray calculated before.</param>
  // <returns>The result of these manipulations.</returns>
  private static int DEncrypt(int left, int right, int scheduleIndex, int firstSaltTranslator, int secondSaltTranslator, int[] schedule) {
    int firstInt, secondInt, thirdInt;

    thirdInt = right ^ (right >>> 16);
    secondInt = thirdInt & firstSaltTranslator;
    thirdInt = thirdInt & secondSaltTranslator;

    secondInt = (secondInt ^ (secondInt << 16)) ^ right ^ schedule[scheduleIndex];
    firstInt = (thirdInt ^ (thirdInt << 16)) ^ right ^ schedule[scheduleIndex + 1];
    firstInt = (firstInt >>> 4) | (firstInt << 28);

    left ^= (m_SPTranslationTable[1][firstInt & 0x3F]
            | m_SPTranslationTable[3][(firstInt >>> 8) & 0x3F]
            | m_SPTranslationTable[5][(firstInt >>> 16) & 0x3F]
            | m_SPTranslationTable[7][(firstInt >>> 24) & 0x3F]
            | m_SPTranslationTable[0][secondInt & 0x3F]
            | m_SPTranslationTable[2][(secondInt >>> 8) & 0x3F]
            | m_SPTranslationTable[4][(secondInt >>> 16) & 0x3F]
            | m_SPTranslationTable[6][(secondInt >>> 24) & 0x3F]);

    return left;
  }

  // Calculates two ints that are used to encrypt the password.
  // <param name="schedule">The schedule table calculated earlier.</param>
  // <param name="firstSaltTranslator">The first translated salt character.</param>
  // <param name="secondSaltTranslator">The second translated salt character.</param>
  // <returns>2 ints in an array.</returns>
  private static int[] Body(int[] schedule, int firstSaltTranslator, int secondSaltTranslator) {
    int left = 0;
    int right = 0;
    int tempInt;

    for (int index = 0; index < 25; index++) {
      for (int secondIndex = 0; secondIndex < m_desIterations * 2; secondIndex += 4) {
        left = DEncrypt(left, right, secondIndex, firstSaltTranslator, secondSaltTranslator, schedule);
        right = DEncrypt(right, left, secondIndex + 2, firstSaltTranslator, secondSaltTranslator, schedule);
      }

      tempInt = left;
      left = right;
      right = tempInt;
    }

    tempInt = right;
    right = (left >>> 1) | (left << 31);
    left = (tempInt >>> 1) | (tempInt << 31);

    left &= 0xFFFFFFFF;
    right &= 0xFFFFFFFF;

    int operationResults[] = new int[2];

    PermOperation(right, left, 1, 0x55555555, operationResults);
    right = operationResults[0];
    left = operationResults[1];

    PermOperation(left, right, 8, 0x00FF00FF, operationResults);
    left = operationResults[0];
    right = operationResults[1];

    PermOperation(right, left, 2, 0x33333333, operationResults);
    right = operationResults[0];
    left = operationResults[1];

    PermOperation(left, right, 16, 0xFFFF, operationResults);
    left = operationResults[0];
    right = operationResults[1];

    PermOperation(right, left, 4, 0x0F0F0F0F, operationResults);
    right = operationResults[0];
    left = operationResults[1];

    int[] singleOutputKey = new int[2];
    singleOutputKey[0] = left;
    singleOutputKey[1] = right;

    return singleOutputKey;
  }

  // Automatically generate the encryption salt (2 random printable characters for use in the encryption) and call the Crypt() method.
  // <param name="textToEncrypt">The text that must be encrypted.</param>
  // <returns>The encrypted text.</returns>
  public static String crypt(char[] textToEncrypt) {
    Random randomGenerator = new Random();
    int maxGeneratedNumber = m_encryptionSaltCharacters.length;
    int randomIndex;
    char encryptionSalt[] = new char[3];

    randomGenerator.setSeed(System.currentTimeMillis());
    encryptionSalt[2] = 0;  //NULL term (not required)
    for (int index = 0; index < 2; index++) {
      randomIndex = (randomGenerator.nextInt() & 0xffffff) % maxGeneratedNumber;
      encryptionSalt[index] = m_encryptionSaltCharacters[randomIndex];
    }
    return crypt(encryptionSalt, textToEncrypt);
  }

  private static boolean hasChar(char chars[], char ch) {
    for (int a = 0; a < chars.length; a++) {
      if (chars[a] == ch) {
        return true;
      }
    }
    return false;
  }

  // Encrypts the specified string using the Unix crypt algorithm.
  // <param name="encryptionSalt">2 random printable characters that are used to randomize the encryption.</param>
  // <param name="textToEncrypt">The text that must be encrypted.</param>
  // <returns>The encrypted text.</returns>
  public static String crypt(char[] encryptionSalt, char[] textToEncrypt) {
    if (encryptionSalt.length < 2) {
      return null;
    }

    char firstSaltCharacter = encryptionSalt[0];
    char secondSaltCharacter = encryptionSalt[1];

    //make sure salt chars are valid
    if (!hasChar(m_encryptionSaltCharacters, firstSaltCharacter)) {
      return null;
    }
    if (!hasChar(m_encryptionSaltCharacters, secondSaltCharacter)) {
      return null;
    }

    // Make sure the string builder is big enough AND filled with 13 characters (the length of the encrypted password).
    // We will use the index operator to set them, but when the characters are not present, even though the string builder
    // has enough capacity, it will throw an exception.
    byte encryptionBuffer[] = new byte[13];  //"*************";
    encryptionBuffer[0] = (byte) firstSaltCharacter;
    encryptionBuffer[1] = (byte) secondSaltCharacter;

    // Use the ASCII value of the salt characters to lookup a number in the salt translation table.
    int firstSaltTranslator = m_saltTranslation[firstSaltCharacter];
    int secondSaltTranslator = m_saltTranslation[secondSaltCharacter] << 4;

    // Build the first encryption key table by taking the ASCII value of every character in the text to encrypt and
    // multiplying it by two. Note how the cast will not lose any information. The highest possible ASCII character
    // in a password is the tilde (~), which has ASCII value 126, so the highest possible value after the
    // multiplication would be 252.
    byte encryptionKey[] = new byte[8];
    for (int index = 0; index < 8 && index < textToEncrypt.length; index++) {
      int shiftedCharacter = textToEncrypt[index];
      encryptionKey[index] = (byte) (shiftedCharacter << 1);
    }

    int[] schedule = SetDESKey(encryptionKey);
    int[] singleOutputKey = Body(schedule, firstSaltTranslator, secondSaltTranslator);

    byte binaryBuffer[] = new byte[9];

    IntToFourbytes(singleOutputKey[0], binaryBuffer, 0);
    IntToFourbytes(singleOutputKey[1], binaryBuffer, 4);
    binaryBuffer[8] = 0;

    int binaryBufferIndex = 0;
    int passwordCharacter;
    int bitChecker = 0x80;
    boolean isAnyBitSet, bitCheckerOverflow;
    for (int index = 2; index < 13; index++) {
      passwordCharacter = 0;
      for (int secondIndex = 0; secondIndex < 6; secondIndex++) {
        passwordCharacter <<= 1;
        isAnyBitSet = ((binaryBuffer[binaryBufferIndex] & bitChecker) != 0);
        if (isAnyBitSet) {
          passwordCharacter |= 1;
        }

        bitChecker >>>= 1;
        bitCheckerOverflow = (bitChecker == 0);
        if (bitCheckerOverflow) {
          binaryBufferIndex++;
          bitChecker = 0x80;
        }
      }
      encryptionBuffer[index] = (byte) m_characterConversionTable[passwordCharacter];
    }
    return new String(encryptionBuffer);
  }
}
